Doomed Pine Island Glacier Releases Guam-Sized Iceberg into Southern Ocean

Science has confirmed it. Human-caused warming is killing Antarctica’s massive Pine Island Glacier (PIG). And this week’s release of a chunk of ice larger than Guam into the southern ocean is just one of the many major losses that will occur as part of what is now an inevitable demise of one of the world’s greatest glaciers.

The iceberg calved from Antarctica's Pine Island Glacier last November, according to NASA. The crack that produced it was first spotted in 2011. Since November, B31 has drifted out of Pine Island Bay and into the Amundsen Sea off the western side of the continent. 'The iceberg is now well out of Pine Island Bay and will soon join the more general flow in the Southern Ocean, which could be east or west in this region," iceberg researcher Grant Bigg from the University of Sheffield in England said in the NASA statement. Once that happens, the researchers worry it will be difficult track the iceberg during the long weeks of darkness that comprise the Antarctic winter. And don't expect it to melt. An iceberg of that size could hang around for a year or more, Robert Marsh, a scientist at the University of Southampton in England, said last year. The largest iceberg ever recorded was called B15. With an area of 4,250 square miles -- about the size of the state of Connecticut or the island of Jamaica - it calved off Antarctica's Ross Ice Shelf in March 2000. B15 has since broken up, but parts of it still exist around the Antarctic today.

Heat-Charged Blow to The Soft Underbelly of Antarctic Ice Shelves

As human greenhouse gas emissions caused the world’s oceans to warm, upwelling currents delivered a portion of that heat to the continental shelf zone surrounding Antarctica. A fortress of ice, numerous glacial ice shelves thrust out from this frozen land and drove deep into the sea floor. Ocean-fronting glaciers featured submerged sections hundreds of feet below the sea surface.

The warming currents encountered these massive ice faces, eroding their undersides and providing pathways for ocean waters to invade many miles beneath the glaciers. These invasions subjected the vulnerable ice shelves not only to the heat forcing of an ever-warming ocean, but also to wave and tidal stresses. The reduction in grounding and the constant variable stresses set the glaciers into a rapid seaward motion.

Antarctica’s most vulnerable glaciers lie along its western out-thrust. Two, Thwaites and the Pine Island Glacier, have recently seen very rapid increases in forward speed. Of these, the Pine Island Glacier, according to a recent study, is undergoing the process of an irreversible collapse. What this means is that the glacier’s speed of forward motion is now too great to be halted. Inevitably, even if the climate were to cool, the entire giant glacier will be launched into the world’s oceans where it will entirely melt out.

Guam-Sized Chunk of Ice to be One of Many

The Pine Island Glacier is massive, covering a total area of 68,000 square miles and, in some locations, rising to over 2,000 feet in height. It represents 10% of all the ice in the West Antarctic Ice Sheet, holding enough liquid water to raise sea levels by between 1 and 2.5 feet all on its own. And the now destabilized PIG is bound to put added stresses on the adjacent Thwaites glacier together with almost the entire West Antarctic ice system. Over recent years, PIG’s forward speed has accelerated. Increasing forward velocity by 73 percent from 1974 to 2007. Surveys made since that time show an even more rapid pace. By January of this year, studies were finding that PIG had entered a sate of irreversible collapse. So it is little wonder that enormous chunks of ice are breaking off from this massive glacier and drifting on out into the Southern Ocean.

As of early this week, the immense ice island dubbed B31 measuring 12×24 miles in size (nearly 290 square miles), slid off its temporary grounding on the sea bottom and began its journey out into the Southern Ocean. There it will remain for years, plaguing the world’s shipping lanes as it slowly disintegrates into a flotilla of icebergs. It is just the most recent event in the now ongoing decline of PIG. And we can expect many, many more major ice releases as this vast Antarctic glacier continues its dive to the sea. More

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Our Perpetual Ocean

This is an animation of ocean surface currents from June 2005 to December 2007 from NASA satellites. Watch how bigger currents like the Gulf Stream in the Atlantic Ocean and the Kuroshio in the Pacific carry warm waters across thousands of miles at speeds greater than four miles per hour (six kilometers per hour); how coastal currents like the Agulhas in the Southern Hemisphere move equatorial waters toward Earth's poles; and how thousands of other ocean currents are confined to particular regions and form slow-moving, circular pools called eddies. Credit: NASA/SVS
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The swirling flows of tens of thousands of ocean currents were captured in this scientific visualization created by NASA's Goddard Space Flight Center in Greenbelt, Md.

"There is also a 20-minute long tour, which shows these global surface currents in more detail," says Horace Mitchell, the lead of the visualization studio. "We also released a three-minute version on our NASA Visualization Explorer iPad app."

Both the 20-minute and 3-minute versions are available in high definition here: http://svs.gsfc.nasa.gov/goto?3827

The visualization covers the period June 2005 to December 2007 and is based on a synthesis of a numerical model with observational data, created by a NASA project called Estimating the Circulation and Climate of the Ocean, or ECCO for short. ECCO is a joint project between the Massachusetts Institute of Technology and NASA's Jet Propulsion Laboratory in Pasadena, Calif. ECCO uses advanced mathematical tools to combine observations with the MIT numerical ocean model to obtain realistic descriptions of how ocean circulation evolves over time.

These model-data syntheses are among the largest computations of their kind ever undertaken. They are made possible by high-end computing resources provided by NASA's Ames Research Center in Moffett Field, Calif.

ECCO model-data syntheses are being used to quantify the ocean's role in the global carbon cycle, to understand the recent evolution of the polar oceans, to monitor time-evolving heat, water, and chemical exchanges within and between different components of the Earth system, and for many other science applications.

In the particular model-data synthesis used for this visualization, only the larger, ocean basin-wide scales have been adjusted to fit observations. Smaller-scale ocean currents are free to evolve on their own according to the computer model's equations. Due to the limited resolution of this particular model, only the larger eddies are represented, and tend to look more 'perfect' than they are in real life. Despite these model limitations, the visualization offers a realistic study in both the order and the chaos of the circulating waters that populate Earth's ocean.

Data used by the ECCO project include: sea surface height from NASA's Topex/Poseidon, Jason-1, and Ocean Surface Topography Mission/Jason-2 satellite altimeters; gravity from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment mission; surface wind stress from NASA's QuikScat mission; sea surface temperature from the NASA/Japan Aerospace Exploration Agency Advanced Microwave Scanning Radiometer-EOS; sea ice concentration and velocity data from passive microwave radiometers; and temperature and salinity profiles from shipborne casts, moorings and the international Argo ocean observation system. More

 

US East Coast Sea Surface Temperatures In 2012 Highest In 150 Years

02 May 2, 2013
Countercurrents.org

NOAA reports that 2012 brought the warmest recorded sea surface temperatures in 150 years for the US east coast between Cape Hatteras, N.C. and the Gulf of Maine.

Using satellite and ship-board measurements, NOAA's Northeast Fisheries Science Center (NEFSC) reported that average surface temperatures reached 57.2 F (14 C) in 2012, beating the previous record set in 1951. 2012's temperature rise also marked the largest single-year increase since records began in 1854 and one of only five times that average temperatures have jumped by more than 1.8 F (1 C).

“Changes in ocean temperatures and the timing and strength of spring and fall plankton blooms could affect the biological clocks of many marine species, which spawn at specific times of the year based on environmental cues like water temperature,” said Kevin Friedland, a scientist in the NEFSC Ecosystem Assessment Program, in a press statement.

Research has shown that rising ocean temperatures as a result of climate change may also pose a threat to the ocean's single-celled phytoplankton, such as algae. They are not only the foundation of the marine food chain, Climate Central explains. They also "consume about half of the carbon dioxide that enters the atmosphere."

Scientists aren't certain of the extent to which rising temperatures will impact these organisms, or how quickly they will be able to adapt, but slowed phytoplankton growth could mean more CO2 remaining in the atmosphere.

Atmospheric CO2 concentrations are at their highest level in human history and continue to rise.

Increased carbon dioxide in the air -- as a result of human activities like the burning of fossil fuels -- also means more CO2 dissolved in the world's oceans. NOAA chief Jane Lubchenco told the Associated Press in 2012, ocean acidification is climate change's "equally evil twin."

"It's yet another reason to be very seriously concerned about the amount of carbon dioxide that is in the atmosphere now and the additional amount we continue to put out," she told AP. "It is going to be a long time before we can stabilize and turn around the direction of change simply because it's a big atmosphere and it's a big ocean."

Rising sea level

Another report [2] from Georgetown, S.C. said:

Effects of higher sea level are very clear down a winding dirt road in Georgetown County where acres of what was once a forested wetland have morphed into a salt marsh of dead trees jutting toward the sky.

"When you go into the field, you really see a lot of trees dying. That's the first thing that catches your eye," said Alex Chow, who teaches biosystems engineering at Clemson University's Baruch Institute of Coastal Ecology and Forest Science at Hobcaw Barony, a wildlife refuge northeast of Georgetown.

Chow and two other colleagues at the institute used aerial photos to map how the salt water has advanced into freshwater Strawberry Swamp from nearby Winyah Bay.

Their study found that over the past six decades, the amount of salt marsh in the area has increased from about 4 acres to more than 16 acres. The study was published in December in "Wetland Science and Practice," the quarterly journal of the international Society of Wetland Scientists.

"Over long periods – and what we looked at is over 60 years – the maritime forest retreats at approximately the same rate sea level rises," said Tom Williams, a professor emeritus of forestry and natural resources who is a co-author.

Bo Song, assistant professor of forestry and natural resources, also contributed to the study.
The study notes that along the state's north coast, the sea level rise has average 3 to 4 millimeters a year during the past century or so.

William Conner, a professor of forestry and natural resources at the institute, said that what is happening in Strawberry Swamp is similar to what is happening throughout the Southeast, where the shorelines tend to be flattened. The dead trees along the Cape Fear River in Wilmington are an example, he said. In areas where rivers are dredged for shipping, it also makes it easier for salt water to impinge on freshwater areas.

"It's been a little more dramatic in recent years," he said.

"Based on the calculations in this study, you can see it's happening much faster in the past two decades," Chow said. More

 

Whats up with sea level rise - NASA

Earlier today, in a NASA Google+ Hangout on Air on these questions and more:

How much and how fast will sea level rise in the coming decades? What makes sea level rise hard to predict? Who will be affected?

You can watch it above.

There was a Twitter discussion, as well, centering on the #sealevel hashtag.